The acquired immunodeficiency syndrome (AIDS) is probably the most serious challenge currently facing biomedicine and the health-care professions. The syndrome and allied conditions produce a wide range of serious oral lesions which are, as yet, poorly understood. This program project integrates the activities of clinical and laboratory investigators in a broadly-based long- term interdisciplinary study of the oral manifestations of AIDS and associated diseases. The program project proposal is new but the key investigators have worked together effectively for several years. The program is organized as a core and three separate but interrelated research projects. The first of these involves studies of the epidemiology of the oral manifestations of HIV infection utilizing eight cohorts which are the subjects of investigation in San Francisco. The second project concentrates on the etiology, pathogenesis and clinical aspects of the oral manifestations of human immunodeficiency virus (HIV) disease. The third project will involve investigations of the oral features of simian AIDS. It is the overall goal of the project to enable the several investigator groups to work individually and together in order to broaden knowledge of the prevalence, incidence, clinical features and mechanism of the oral consequences of HIV infection. The ultimate intention is to bring such investigations to clinical application in the prevention and treatment of these diseases.